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Do you think your dish is immune to lighting? Think again…

Discussion in 'DIRECTV Installation/MDU Discussion' started by sptrout, Oct 8, 2007.

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  1. mchaney

    mchaney Godfather

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    Aug 17, 2006
    Good point. And there are direct strikes and strikes by feeders that come off the main bolt. A grounding wire can help in the latter, which accounts for most lightning strikes.

    Mike
     
  2. hilmar2k

    hilmar2k Hall Of Fame

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    Mar 18, 2007
    You'd be surprised how much current that little grounding wire can carry for a really short period of time. I've seen planty of reports of the entire strike being carried to ground entirely by the gorunding wire. Not that I would count on that, but it certainly can happen.
     
  3. PoitNarf

    PoitNarf New Member

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    Aug 19, 2006
    Actually, lightning travels from the ground to the clouds (most of the time anyways).
     
  4. JeffBowser

    JeffBowser blah blah blah

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    Dec 21, 2006
    As I usually like to say, when I see a statement that appears to violate the very laws of physics, can you cite references ?

     
  5. n3ntj

    n3ntj Hall Of Fame

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    Dec 18, 2006
    Lancaster,...
    Nothing will prevent a lighting strike from doing damage or causing injury/death.. proper grounding will only help minimize damage in case of a nearby strike or built-up charge.
     
  6. mchaney

    mchaney Godfather

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    Aug 17, 2006
    Ever see the demonstration of how researchers force lightning to strike by sending a rocket up in the sky attached to a very thin wire on the order of filament gauge? The lightning follows the wire all the way to the ground. Of course, most of the wire is vaporized, but once the strike follows that path, it rarely jumps off to something else. Once lightning takes a particular path, it tends to follow that path until the charge dissipates. This has a technical term and it was mentioned on the show but I don't remember the term.

    Mike
     
  7. bret4

    bret4 DBSTalk Club Member

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    Nov 22, 2006
    The ground wire may not take that kind of power but it may help redirect it to the path of least resistance before it is burned away.

    Grounding does reduce the buildup of static charge in the hope of reducing the chance of a lightning strike on the item grounded. If all else fails it takes some of the power to ground.
     
  8. Kansas Zephyr

    Kansas Zephyr Hall Of Fame

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    Jun 29, 2007
    stepped leader, then dart leaders
     
  9. JeffBowser

    JeffBowser blah blah blah

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    Dec 21, 2006
    All that wire did was create the initial (and artificial) stepped leader. After that, the wire had nothing to do with anything - as you pointed out, it was vaporized. The bolt is now following the charged path through nothing but thin air.

    Nice article on the basics here: http://science.howstuffworks.com/lightning.htm

     
  10. Kansas Zephyr

    Kansas Zephyr Hall Of Fame

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    Jun 29, 2007
    +1
     
  11. aim2pls

    aim2pls Icon

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    Jun 18, 2007
    AHHHHHHHH S O M E O N E ...."finally" understands
     
  12. Kansas Zephyr

    Kansas Zephyr Hall Of Fame

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    Jun 29, 2007
    Well, the current flow can be from:
    1) Cloud to Cloud CC
    2) Intracloud IC
    3) Cloud to Ground CG
    4) Ground to Cloud GC
     
  13. joe diamond

    joe diamond Hall Of Fame

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    Feb 28, 2007
    I'm gonna add this thread to my notes:

    We needed this. My favorite expert..and we all have them..told me the ground wire would just "burn open" before the majority of the pulse followed the wire.
    I have see this.

    I did once pass on an installation. I told the call center the third floor apartment was impossible to ground per local code. I then noted that
    the Dish to ground block dual cable would need to be 150 feet long and then
    return to the apartment, exceeding the practical limits of the system (300+ft dish to receiver).

    The CSR just got another tech to go attach the dish to the third floor roof and drop the line into the customer's apartment; no ground.

    Business as usual. It is still there. Is there a lesson?

    Joe
     
  14. JeffBowser

    JeffBowser blah blah blah

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    Dec 21, 2006
    :D Yeah the NEC is nice, but it sure can be impractical in real life sometimes :lol:

     
  15. inothome

    inothome Mentor

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    Sep 4, 2007
    FWIW you can see the grounding block in the video, so there was some grounding anyway.
     
  16. Clato

    Clato Banned User

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    Aug 30, 2007
    hello all i just got ogg the phone with the Tec rep and gave hime this cernarion,(ie lightening hitting tree, jumping to dish & into home,) and was told,"'that would be like a direct hit or a near hit and NO nothing that has been made would protect you, in a case like that is why we offer the lifetime $125,000.00 connected equipment guarantee in writing

    I purchased mine in May this year
    http://www.bestbuy.com/site/olspage...power&lp=5&type=product&cp=1&id=1099396538742


    so if your going to get a "surge protector" get one that has a connected equipment guarantee with it.
    clato
     
  17. aim2pls

    aim2pls Icon

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    Jun 18, 2007
    looking at the video closely ... you will see that the dish is UNTOUCHED .... looks more like the tree took the hit ... then to the ground to the house (in total) then up the coax to the grounding block (scorched area) then back down to the ground ... aka PROTECTING the dish ....... news media are "actors" reporting their opinions ..... in this case grounding the dish did little to nothing
     
  18. hilmar2k

    hilmar2k Hall Of Fame

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    Mar 18, 2007
    I said it was carried to ground, not to "the" ground.
     
  19. jganson

    jganson New Member

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    Jan 30, 2007
    If your dish or LNB took a direct hit, they would almost certainly show damage. It's possible that the lightning strike led to your damaged LNB, but I doubt it was a direct hit if you don't see damage.

    I was camping in Yellowstone when lightning hit a tree in my campsite. It traveled down the tree, through the roots and arced out of the ground in several places. In addition to hitting my legs, it also hit my truck (frying the computer) and an older tent with metal poles in the next campsite over. (3 different directions from the tree that was hit.) The truck and the tent pole each had a very distinct burn mark on them. (The tree itself exploded and the falling top portion missed killing the people in that tent by just a few feet.)
     
  20. ghostdog

    ghostdog AllStar

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    Jul 6, 2007
    Any idea idea how tv, cellular and radio antenna's are protected?
     
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